1. The Field of the Invention
The present invention relates to a method to provide isolation within a zone of a wellbore lined with a slotted liner by placing an expandable liner within the zone to be isolated.
2. The Prior Art
There is a great deal of prior art relating to isolating portions of a wellbore for various reason. For example, a zone may be producing water or gas and needs to be shut off for more effective production of the petroleum being recovered. Also, a zone may be producing sand or collapsing and creating debris and needs to be isolated to maintain and efficient operation. However, different problems arise when the wellbore has been completed with the insertion of a known slotted liner.
One example of the prior art is U.S. Pat. No. 5,366,012 which describes a method of completing uncased sections of a wellbore by placing, at a predetermined position in the wellbore, a liner which is provided with a plurality of overlapping slots. The upper end of the liner is fixed in place and an upwardly tapering expansion mandrel is drawn upwardly through the slotted liner expanding it outwardly to engage the walls of the wellbore. This circumferentially outward movement is facilitated by the opening of the slots, together with a slight shortening of the overall length of the liner. Slotted liner completions of this type leave an annular area around the slotted liner which makes zonal selectivity nearly impossible.
Another suitable method for sealing between a lining and wellbore, casing or pipeline is shown in U.S. Pat. No. 5,494,106. This patent describes a deformable annular seal which is lowered into the wellbore in a deformed or contracted state, which does not impede insertion. Once in place the seal is expanded. During expansion of the seal it is hardened to form a substantially permanent repair.
Another method for lining a casing is shown in U.S. Pat. No. 5,454,419 in which a tubular polymeric material is lowered into the wellbore in a stretched condition, due to a series of weights attached to the leading or bottom end. When properly positioned, the weights are released and the tubular material returns to its normal condition in which it presses against the walls to the wellbore.